What a difference a year makes. Last autumn Arsene Wenger was generally seen bent double on the touchline, his agony at his team's decline evident in his every Basil Fawlty contortion.

Now he is smiling again, his humour restored, his sarcasm towards the media re-sharpened ("You really should be a coach," he mocked one quizzical reporter at Upton Park).

But here he was leaving east London twinkling, thrilled not only with the result, not only with the manner of his team's comeback, but with the fact goals were shared among his forwards.

Even new recruit Olivier Giroud scored a smart goal, the sort of instinctive finish that seemed beyond him when he first arrived from France.

What was making Wenger smile even more, however, was further evidence that he may well have pulled off the transfer coup of his career.

Once again Santi Cazorla (right) was the man who made the difference, his dipping, swerving shot from the edge of the area finally deflating a perky, determined home side.

And that goal -- worth his inclusion on its own -- was by no means his only contribution. He buzzed around the pitch, providing his team-mates with a constant flow of clever passes.

"He makes everybody a better player," said Wenger of the Spaniard. And he has a point.

With the quick-witted Lukas Podolski abetting him in the visitors' midfield, he was simply too sharp, too subtle, too elusive for a home side whose industry could not be faulted.

Watching Kevin Nolan panting in his wash, what makes him so slippery is the fact he is so comfortable using either foot.

Asked whether the player favours his right or his left, Wenger confessed he had no idea.

"When you watch him play, you don't know what foot he is," the manager said.

Not that, to start with, he had it all his way. West Ham began well, absolutely playing to their strengths. Andy Carroll in particular was soon punching aggressive holes into the always porous Arsenal backline.

So diverted were the Arsenal centre-backs by the striker, they barely noticed Mohamed Diame stealing past Aaron Ramsey into an inviting space to open the scoring.

A year ago, this might have been the signal for Arsenal to crumble. But here they really did respond, with a lovely finish from Theo Walcott sandwiched between Giroud and Cazorla's efforts. Now, they really do look a team that really has belief that it can overcome adversity. Now they have Cazorla.

"It is too early to say what effect he will have on us," said Wenger. "But when you consider that this type of player is not even playing for Spain, it shows you how good they are."